Moths and climate change

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Moths and other wildlife are being affected by climate change. Species have always evolved to adapt to changing conditions, and will continue to do so. The problem with man-made climate change is that it is happening so quickly that our wildlife may not be able to evolve and adapt fast enough.

So far there have already been some winners and some losers as a result of climate change. One moth which has suffered is the beautiful Garden Tiger. This moth used to be a familiar sight in British gardens. Its brown furry caterpillars, known as woolly bears, were often seen wandering across open ground while looking for a suitable place to pupate. Between 1968 and 2002 numbers of the Garden Tiger fell by an alarming 89%. This seems to be because the caterpillars are adapted to survive long frosty winters, so they don't do well in the mild wet winters and warmer springs of recent years. Sadly, this species is predicted to decline even further.

Meanwhile another lovely member of the tiger moth family is thriving. The Scarlet Tiger is found in many habitats, including gardens, and flies during the daytime in June and July. It particularly likes damp places and is often associated with Comfrey, a favourite food of the caterpillar. This moth is mainly found in the West Country, from Gloucestershire down to Cornwall (though it's much less common in the far west), and in south Wales, but it's also found in central southern England, north to Oxfordshire. In recent years it seems to have been spreading further north, which is probably a result of climate change.

Many other species are also spreading north, probably seeking cooler areas as southern areas become warmer through climate change. For example the Lime Hawk-moth is advancing through northern England and the Cinnabar is spreading further into Scotland. Moths which already live in cool areas in northern Britain or on mountains may face problems, as they will have nowhere further north or higher up to find the cooler conditions they need.

Like many other species, moths are also likely to face problems as the changing climate alters the timing of spring and the growth of their food plants. Moth life-cycles have evolved to be synchronised with their food-plants, but climate change is affecting the emergence of leaves on trees and other plants. This in turn can have disastrous impacts on the breeding birds which rely on a supply of caterpillars to feed their young.

It is hard to predict exactly what will happen to our native moths as result of climate change. This is partly because climate change itself is unpredictable. Although there will be an overall rise in global temperatures, this will affect the climate and weather patterns differently in different parts of the world. While some places may become hotter or drier, others may become cooler or wetter, and there may be greater variations in the weather from one year to the next, making it even harder for species to adapt. For this reason it is vital that we give moths and other wildlife even more help through various conservation efforts, as well as trying to reduce our carbon emissions to limit climate change. Use the links on the left to find out how you can help moths.